KR20120139675A - Method for producing propylene oxide - Google Patents

Abstract

It is an object to provide a process for producing propylene oxide from propylene, hydrogen and oxygen at an improved reaction rate. The present invention provides a process for producing propylene oxide, comprising the step of reacting propylene, hydrogen, and oxygen in a liquid phase in the presence of a Pd-supported catalyst, a titanosilicate catalyst, and a Pd-free carbon material.

Description

Process for the production of propylene oxide {METHOD FOR PRODUCING PROPYLENE OXIDE}

As a manufacturing method of a propylene oxide, the manufacturing method including the process of reacting propylene, oxygen, and hydrogen in presence of a noble metal-supported catalyst and a titanosilicate catalyst is known (for example, refer nonpatent literature 1).

On the other hand, a high efficiency propylene oxide manufacturing method is industrially preferable.

 Applied Catalysis A: General 213, (2001), 163-171

There is a need for a method for efficiently producing propylene oxide from propylene, oxygen and hydrogen.

MEANS TO SOLVE THE PROBLEM The present inventors came to this invention as a result of earnestly examining in order to solve the said subject.

That is, the present invention provides:

[1] a process for producing propylene oxide, comprising the step of reacting propylene, hydrogen and oxygen in a liquid phase in the presence of a Pd-supported catalyst, a titanosilicate catalyst and a Pd-free carbon material;

[2] the method according to [1], wherein the Pd-supported catalyst consists of a carrier and Pd supported by the carrier, and the Pd-free carbon material does not form a carrier of the Pd-supported catalyst;

[3] the method according to [1], wherein the Pd-supported catalyst comprises at least one carrier selected from the group consisting of silica, alumina, activated carbon and carbon black;

[4] the method according to [1], wherein the Pd-supported catalyst comprises a carrier selected from the group consisting of activated carbon and carbon black;

[5] the method according to any one of [1] to [4], wherein the Pd-free carbon material is activated carbon, carbon black, or a mixture thereof;

[6] the method according to any one of [1] to [4], wherein the Pd-free carbon material is activated carbon;

[7] The method according to any one of [1] to [6], wherein the process further comprises reacting propylene, hydrogen, and oxygen in the liquid phase in the presence of a polycyclic compound having 2 to 30 rings;

[8] the method according to [7], wherein the polycyclic compound is a condensed polycyclic aromatic compound; And

[9] The method according to [7], wherein the polycyclic compound contains anthraquinone.

According to the present invention, propylene oxide can be prepared from propylene, hydrogen and oxygen with improved production rates.

1 is an X-ray diffraction pattern of Ti-MWW precursor A. FIG.
2 is a UV-visible absorption spectrum of Ti-MWW precursor A. FIG.
3 is the UV-visible absorption spectrum of titanosilicate B. FIG.

The production process of the present invention includes a process of reacting propylene, hydrogen and oxygen in a liquid phase in the presence of a Pd-supported catalyst, a titanosilicate catalyst and a Pd-free carbon material. Hereinafter, this embodiment will be referred to as the "main process", and the reaction of propylene, hydrogen and oxygen will be referred to as the "main reaction", and specific embodiments of the present invention will be described.

<Pd-Free Carbon Material>

The Pd-free carbon material used in this process means a carbon material substantially free of Pd (palladium). In the present context, "substantially free of Pd" means that the Pd content weight percentage (hereinafter referred to as "Pd content") is less than 0.01 wt%, and the carbon material means a material composed mainly of carbon. Examples of such Pd-free carbon materials include activated carbon; Carbon black; Carbon nanotubes; Mesoporous carbon; Carbon fiber; Fullerene-like compounds such as fullerene or C70; Graphite; And diamonds. The above-mentioned Pd-free carbon materials have different names depending on their shape, crystal form, etc., but all are mainly composed of carbon. In addition, the above-mentioned carbon materials all have the advantage that they are readily available from the market that the Pd content is less than 0.01% by weight. In addition, commercially available Pd-free carbon materials can also be prepared by suitable analytical methods such as X-ray analysis, such as Fundamental Parameter (FP), or IPC emission spectrometry (analytical method with a lower limit of analysis of Pd content of less than 0.01% by weight). It can be provided to the present invention after confirming that the Pd content is less than 0.01% by weight.

In the present invention, the Pd-free carbon material does not carry Pd; Form particles that consist essentially of carbon atoms. This particle is separate from the Pd-supported catalyst in the liquid phase.

The Pd-free carbon material can be activated by oxidation or the like. When activating the Pd-free carbon material, propylene oxide can be obtained more efficiently. Examples of methods for such activation (activation methods) include:

Contacting and activating the Pd-free carbon material with water vapor at a temperature of 750 ° C. or higher;

Contacting and activating a Pd-free carbon material with carbon dioxide at a temperature condition of 850-1100 ° C .;

A method comprising contacting a Pd-free carbon material with an oxidizing gas such as an oxygen-containing gas; And

Activation method using chemicals such as zinc chloride, phosphoric acid, sulfuric acid, nitric acid, calcium chloride and sodium hydroxide.

Here, the specific activation method will be described. For example, in the case of using diamond as the Pd-free carbon material, a method is known in which a commercially available fine diamond powder is air oxidized at a temperature of 450 ° C. for about 1 hour to form diamond oxide. The activation method is described in Japanese Laid-Open Patent Publication No. 2002-177783). Furthermore, for example, when using activated carbon derived from plants such as sawdust or palm husk as a Pd-free carbon material, the material includes activating the carbon material in contact with water vapor at a temperature condition of 750 to 900 ° C. , And the like can be further activated by a method comprising activating the carbon material in contact with zinc chloride at a temperature of 600 to 750 ℃.

Industrially, it is desirable that the Pd-free carbon material used in the present process be inexpensive. In view of being inexpensive, a Pd-free carbon material selected from the group consisting of activated carbon, carbon black and graphite is preferred; Activated carbon, carbon black or mixtures thereof is more preferred; Activated carbon is more preferred. In particular, activated carbon is commercially available that has been previously activated by zinc chloride, water vapor, or the like, which is preferable from the viewpoint of availability.

It is also preferable that the Pd-free carbon material should have a large surface area (having a high surface area). The specific surface area (BET specific surface area) by nitrogen gas adsorption as an index according to such a high surface area is preferably 10 m ² / g or more, more preferably 50 m ² / g or more, even more preferably 100 m ² / g or more. Also in view of high surface area, examples of preferred Pd-free carbon materials may include activated carbon and carbon black, among which activated carbon is particularly preferred. The BET specific surface area of commercially available activated carbon or carbon black is generally 10 m ² / g or more, and in particular, activated carbon is commercially available that has a very high surface area of 1000 m ² / g or more. The carbon material is preferably used as a Pd-free carbon material in this step after measuring the BET specific surface area to confirm that the BET specific surface area is 10 m ² / g or more. Similarly, when plural kinds of Pd-free carbon materials are mixed and used, the BET specific surface area of the Pd-free carbon materials after mixing is 10 m ² / Can be set to be more than g. The upper limit of the BET specific surface area of a Pd-free carbon material is about 3000 m ² / g in terms of the availability of the material. In this specification, the BET specific surface area can be measured with a micromeritics automatic surface area analyzer.

It is preferable that the amount of Pd-free carbon material used in the present process should be determined in consideration of the amount of Pd-supported catalyst used together. Specifically, the weight ratio between the Pd-free carbon material and the Pd-supported catalyst is represented by [Pd-free carbon material] / [Pd-supported catalyst], preferably in the range of 1/1 to 1000/1, more preferably Is in the range of 1/1 to 200/1. If the said weight ratio is too small, since sufficient reaction activity is not obtained, the reaction time of this invention can be long. If the weight ratio is too large, it is necessary to make the size of the reactor used in the present process larger than necessary.

<Pd-supported catalyst>

The Pd-supported catalyst used in this step is one in which Pd (palladium) is supported on a carrier, and has a catalytic ability related to the present reaction. The carrier only needs to be capable of supporting Pd, and examples thereof include oxides such as silica, alumina, titania, zirconia and niobia; Niobic acid, zirconic acid, tungstic acid and titanic acid; And carbon materials, and a plurality of mixtures, mixed oxides, and the like selected therefrom may also be used. In this context, the mixed oxide is crystalline aluminosilicate or the like. This carrier is preferably to be readily available as commercially available, more preferably inexpensive. Examples of inexpensive commercially available carriers include niobic acid, activated carbon, carbon black, silica gel, silica, alumina and aluminum-containing zeolites. Examples of commercially available aluminum-containing zeolites include zeolite A, zeolite X, zeolite Y, ZSM-5, zeolite T, zeolite P, zeolite L, zeolite beta, mordenite, ferrierite and carbazite. Among these aluminum-containing zeolites, some are ion-exchanged using sodium ions, potassium ions, calcium ions, ammonium ions and the like to compensate for the lack of charge of aluminum ions. Among those mentioned above, examples of more preferable carriers include those selected from the group consisting of silica, alumina, activated carbon and carbon black; Activated carbon or carbon black is more preferred; Activated carbon is particularly preferred.

The Pd-supported catalyst generally consists of the above-mentioned carrier and Pd supported by the carrier. On the other hand, the Pd-free carbon material not used in the carrier is present separately from the Pd-supported catalyst.

By supporting Pd on the carrier, a Pd-supported catalyst can be prepared. The loading of Pd can be carried out according to methods known in the art. For example, a palladium compound (e.g., palladium chloride and tetraamminepalladium (II) chloride), which is a Pd source, is supported on a carrier by impregnation, or the like, and then the supported palladium compound is reduced with a reducing agent such as hydrogen to reduce Pd-. Supported catalysts can be prepared. In such a manufacturing method, the temperature conditions of 0-500 degreeC are employ | adopted, for example. Supporting the palladium compound on the carrier and / or reduction of the palladium compound can be carried out in the gas phase or in the liquid phase, and the temperature conditions can be appropriately adjusted according to the situation in the gas phase or in the liquid phase. The palladium in the palladium compound supported on the carrier has a positive charge, and a part or all of it is reduced to zero valent palladium to prepare a Pd-carrier catalyst. This reduction is carried out before providing this process, and the Pd-supported catalyst can be prepared in advance. The palladium compound supported on a carrier can be provided to this process, and reduction can be performed in the reactor which performs this process, and a Pd-supported catalyst can be manufactured.

Further examples of another form of Pd-supported catalyst preparation include the use of colloidal palladium as a palladium source. As this method, a method is known that involves first mixing a colloidal palladium solution with a carrier to support palladium on the carrier, then mixing the mixture and drying the filter cake. Since the palladium contained in the colloidal palladium used here is already zero-valent, a commercially available colloidal palladium can be used to manufacture Pd-supported catalyst very simply. The amount of Pd in the total Pd-supported catalyst is generally in the range of 0.01 to 20% by mass, more preferably in the range of 0.1 to 5% by mass.

Although specific examples of the Pd-supported catalyst and its preparation method used in the present process are given above, Pd in the Pd-supported catalyst may be a pure Pd metal or may be a Pd-containing alloy. Examples of metals other than Pd in the alloy include precious metals selected from the group consisting of platinum, ruthenium, gold, rhodium and iridium. Examples of preferred alloys for use in Pd-supported catalysts include palladium / platinum alloys and palladium / gold alloys.

Titanosilicate Catalyst

Titanosilicate catalysts are titanosilicates that have an epoxidation ability to propylene. Hereinafter, the titanosilicate used as a titanosilicate catalyst will be described in detail.

Titanosilicate is a generic term for silicates having 4 coordination Ti (titanium atoms) and has a porous structure. The titanosilicate constituting the titanosilicate catalyst means a titanosilicate having substantially coordination Ti, and the UV-visible absorption spectrum in the wavelength region of 200 nm to 400 nm has a maximum in the wavelength region of 210 nm to 230 nm. Have an absorption peak (see, eg, FIGS. 2 (d) and 2 (e) of Chemical Communications, 1026-1027, (2002)). This UV-visible absorption spectrum can be measured by the diffuse reflection method using a UV-visible spectrophotometer equipped with a diffuse reflection accessory.

The titanosilicates used as the titanosilicate catalysts preferably have pores composed of 10-membered or more oxygen rings in terms of high epoxidation ability to propylene. If the pores are too small, the contact between the reaction raw material (propylene and the like) located in the pores and the active point in the pores may be inhibited, or the mass transfer of the reaction raw materials in the pores may be restricted. In the present context, pores mean those composed of Si—O or Ti—O bonds. The pores may be hemispherical pores called side pockets, and the pores need not penetrate the primary particles of titanosilicate. In addition, "10-membered or more oxygen ring" means that the ring structure has 10 or more oxygen atoms in the narrowest cross section in (a) the pore or (b) the pore inlet. Pores composed of at least 10-membered oxygen rings in titanosilicates can generally be identified by analysis of X-ray diffraction patterns. In addition, if a titanosilicate is a well-known structure, it can confirm easily by comparing with the X-ray diffraction pattern of a well-known thing.

Examples of titanosilicates used as titanosilicate catalysts include titanosilicates described in the following 1 to 7.

1. crystalline titanosilicates having pores composed of 10-membered oxygen rings;

TS-1 having an MFI structure represented by a structure code defined by the International Zeolite Association (IZA) (eg US Pat. No. 4,410,501), TS-2 having a MEL structure (eg, Journal of Catalysis 130, 440-446, (1991)), Ti-ZSM-48 with MRE structure (eg Zeolites 15, 164-170, (1995)), Ti-FER with FER structure (eg, Journal of Materials Chemistry 8, 1685-1686 (1998)).

2. crystalline titanosilicates having pores composed of 12-membered oxygen rings;

Ti-Beta with BEA structure (eg, Journal of Catalysis 199, 41-47, (2001)), Ti-ZSM-12 with MTW structure (eg, Zeolites 15, 236-242, (1995) ), Ti-MOR having a MOR structure (eg, The Journal of Physical Chemistry B 102, 9297-9303, (1998)), Ti-ITQ-7 having an ISV structure (eg, Chemical Communications 761-762). (2000)), Ti-MCM-68 with MSE structure (e.g. Chemical Communications 6224-6226, (2008)), Ti-MWW with MWW structure (e.g. Chemistry Letters 774-775, ( 2000)) and so on.

3. crystalline titanosilicates having pores composed of 14-membered oxygen rings;

Ti-UTD-1 having a DON structure (eg, Studies in Surface Science and Catalysis 15, 519-525, (1995)) and the like.

4. layered titanosilicates having pores composed of 10-membered oxygen rings;

Ti-ITQ-6 (eg, Angewandte Chemie International Edition 39, 1499-1501, (2000)) and the like.

5. layered titanosilicates having pores composed of 12-membered oxygen rings;

Ti-MWW precursors (e.g. European Patent Publication No. 1731515A1), Ti-YNU-1 (e.g. Angewandte Chemie International Edition 43, 236-240, (2004)), Ti-MCM-36 (e.g. For example, Catalysis Letters 113, 160-164, (2007)), Ti-MCM-56 (eg, Microporous and Mesoporous Materials 113, 435-444, (2008)) and the like.

6. mesoporous titanosilicates;

Ti-MCM-41 (eg, Microporous Materials 10, 259-271, (1997)), Ti-MCM-48 (eg, Chemical Communications 145-146, (1996)), Ti-SBA-15 ( See, for example, Chemistry of Materials 14, 1657-1664, (2002)).

7. silylated titanosilicates;

Compounds in which any of the titanosilicates described in 1 to 4 above are silylated, such as silylated Ti-MWW.

"12-membered oxygen ring" means a ring structure having 12 oxygen atoms in the position of (a) or (b) already described in the description of the 10-membered oxygen ring. Likewise, "14-membered oxygen ring" means a ring structure having 14 oxygen atoms in the position of (a) or (b).

The titanosilicate includes a titanosilicate having a layered structure such as a layered precursor of crystalline titanosilicate and a titanosilicate having an extended interlayer distance of the crystalline titanosilicate. The layered structure can be confirmed by electron microscopy or by measuring the X-ray diffraction pattern. A layered precursor means the titanosilicate which forms crystalline titanosilicate by performing a process, such as dehydration condensation, for example. The pores composed of 12-membered or more oxygen rings in the layered titanosilicate can be readily identified from the structure of the corresponding crystalline titanosilicate.

In addition, the titanosilicates 1 to 5 and 7 have pores having a pore size of 0.5 nm to 1.0 nm. This pore size means the longest size in (a) the cross section of the narrowest part in the pore or (c) the cross section of the widest part in the pore entrance, preferably the diameter of this position. This pore size can be measured by analysis of the X-ray diffraction pattern.

Mesoporous titanosilicate is a generic term for titanosilicates with regular mesopores. Regular mesopores means a structure in which mesopores are regularly and repeatedly arranged. Mesopores refer to pores having a pore size of 2 nm to 10 nm.

Silylation of titanosilicate can be carried out by contacting the silylating agent with titanosilicate. Examples of silylating agents include 1,1,1,3,3,3-hexamethyldisilazane and trimethylchlorosilane. Silylation with such silylating agents is described, for example, in EP-A EP1488853A1.

The titanosilicates used as catalysts in connection with the titanosilicate catalysts used in this process are described in detail above, but among the titanosilicates 1 to 7, particularly preferred as titanosilicate catalysts are Ti-MWW and Ti-MWW precursors, and more particularly Preferably Ti-MWW precursor. Of course, such Ti-MWW or Ti-MWW precursors may be silylated and used in titanosilicate catalysts, or Ti-MWW or Ti-MWW precursors may be shaped and used in titanosilicate catalysts in the art.

<Method for producing propylene oxide>

As noted above, the process involves reacting propylene, hydrogen and oxygen in the presence of a Pd-supported catalyst, a titanosilicate catalyst and a Pd-free carbon material to yield propylene oxide. By the action of a Pd-supported catalyst known as a hydrogen peroxide synthesis catalyst, hydrogen peroxide is first formed from hydrogen and oxygen, and the formed hydrogen peroxide and propylene react by the action of a titanosilicate catalyst to form propylene oxide.

Suitable Ti / Si molar ratios of the titanosilicate catalyst for this reaction are generally from 0.001 to 0.1, preferably from 0.005 to 0.05.

This reaction to form propylene oxide proceeds in the liquid phase. Specifically, hydrogen, oxygen and propylene in the gas phase in the reactor are dissolved in a liquid phase, i.e., a solvent comprising a Pd-supported catalyst, a titanosilicate catalyst and a Pd-free carbon material, and under the action of the Pd-supported catalyst, hydrogen and oxygen Hydrogen peroxide reacts in the liquid phase to form hydrogen peroxide, and the hydrogen peroxide and propylene react in the liquid phase to form propylene oxide by the action of a titanosilicate catalyst.

E.g,

Using a Pd-Pt (palladium / platinum alloy) catalyst supported by TS-1 in a methanol / water mixed solvent (eg Applied Catalysis A: General 213, 163-171, (2001));

A method using a titanosilicate catalyst composed of a Pd-supported catalyst (Pd supported by carbon black) and a Ti-MWW or Ti-MWW precursor in an acetonitrile / water mixed solvent (eg WO2007 / 080995); And

Method using a titanosilicate catalyst consisting of Pd-supported catalyst (Pd supported by activated carbon or niobic acid) and Ti-MWW in an acetonitrile / water mixed solvent (eg WO2008 / 090997)

It is known as a reaction for forming propylene oxide from propylene, hydrogen and oxygen by the action of this Pd-supported catalyst and titanosilicate catalyst. However, these documents do not mention the reaction in the present invention, that is, the reaction carried out in the presence of a Pd-free carbon material added as particles different from the Pd-supported catalyst. This reaction is based on the inventors' own knowledge. Even when a carbon material (for example, activated carbon) is used as a carrier of the Pd-supported catalyst, it is important to coexist Pd-free carbon material separately from such a Pd-supported catalyst.

The Pd-free carbon material forms particles substantially consisting of carbon atoms. Thus, even when the Pd-supported catalyst has carbon, the Pd-free carbon material is present as another particle separately from the Pd-supported catalyst.

Specifically, improving the reaction rate and prolonging the lifetime of the Pd-supported catalyst does not increase the amount of carbon relative to the supported amount of Pd in the Pd-supported carbon material (reduces the amount of Pd in the Pd-supported carbon material) but as a carrier of Pd. It can preferably be achieved by co-existing Pd-free carbon material without changing the amount of carbon used. This knowledge was also obtained by the inventors.

The amount of the titanosilicate catalyst can be adjusted according to the type of reactor used in the present process, the type and amount of the Pd-supported catalyst, and the type or amount of the solvent to be described later. When a fixed bed reactor is used as the reactor, the amount of the titanosilicate catalyst is adjusted so that the fixed bed reactor is densely packed with two catalysts (titanosilicate catalyst and Pd-supported catalyst) and a Pd-free carbon material. When using a stirring vessel as the reactor, it is preferable to form a slurry such that two catalysts (titanosilicate catalyst and Pd-supported catalyst) and a Pd-free carbon material can be sufficiently stirred in the solvent described below. For example, the total amount of titanosilicate catalyst, Pd-supported catalyst and Pd-free carbon material is expressed in weight per kg of solvent used, preferably in the range of 0.001 kg / kg to 0.2 kg / kg, more preferably It may range from 0.01 kg / kg to 0.1 kg / kg.

The mass ratio of Pd (Pd / titanosilicate catalyst) of the Pd-supported catalyst to the titanosilicate catalyst is preferably 0.00001 to 1, more preferably 0.0001 to 0.1, even more preferably 0.001 to 0.05.

In addition, the weight ratio between the Pd-supported catalyst and the titanosilicate catalyst can be adjusted according to the ratio of the respective reaction activities. If the activity of the Pd-supported catalyst deteriorates over time during the reaction, it may be reacted by adding a Pd-supported catalyst to the solvent. If the activity of the titanosilicate catalyst deteriorates over time during the reaction, it can be reacted by adding the titanosilicate catalyst to the solvent.

As mentioned above, this reaction takes place in the liquid phase. In order for this reaction to occur in a liquid phase, a solvent is used for this process. For the present reaction, water, an organic solvent or a mixed solvent of water and an organic solvent (hereinafter referred to as "water / organic solvent mixture") can be used. Since the present reaction forms hydrogen peroxide in the reaction system, a water / organic solvent mixture is preferable from the viewpoint that the present process can be carried out more safely. In addition, since water is formed as a by-product during the formation of propylene oxide in the present reaction, the solvent in the liquid phase may be a water / organic solvent mixture as the reaction proceeds even when only an organic solvent is used as the initial solvent. .

Examples of organic solvents that can be used in the reaction include methanol, 1-propanol, 2-propanol, t-butanol, acetone, acetonitrile, toluene, 1,2-dichloroethane, t-butyl methyl ether and 1,4-di Contains oxane. The organic solvent is preferably acetonitrile.

In this reaction, additives, such as a polycyclic compound, can also be coexisted in order to suppress a propane by-product. Use of such an additive can further improve the hydrogen-based propylene oxide selectivity (hydrogen efficiency). Specifically, polycyclic compounds having 2 to 30 rings such as anthracene, tetracene, 9-methylanthracene, naphthalene and diphenyl ether (see, eg, International Publication WO2008-156205); Polycyclic compounds such as triphenylphosphine, triphenylphosphine oxide, benzothiophene and dibenzothiophene (see, eg, International Publication WO99 / 52884); Monocyclic quinoid compounds such as benzoquinone; Condensed polycyclic aromatic compounds such as anthraquinone, 9,10-phenanthraquinone, benzoquinone and 2-ethylanthraquinone (see, for example, JP 2008-106030 A) and the like are known as additives. Of these additives, condensed polycyclic aromatic compounds having 2 to 30 rings are preferred. Moreover, anthraquinone is more preferable among condensed polycyclic aromatic compounds; When using such additives, preference is given to using anthraquinone-containing additives. When a solvent is used in the present reaction, the additive may or may not be dissolved in the solvent; In order to further have the effect of the additive, it is preferable to select the additive to be soluble in a solvent.

The amount of the additive is preferably in the range of 0.001 mmol / kg to 500 mmol / kg, more preferably in the range of 0.01 mmol / kg to 50 mmol / kg, expressed in terms of the amount of substance per kg of solvent.

In addition, in this process, salts containing ammonium ions, alkylammonium ions or alkylarylammonium ions (hereinafter, these salts are collectively referred to as "ammonium salts") can be further used. By using an ammonium salt in a liquid phase, the utilization efficiency of hydrogen in this reaction can be improved. Examples of ammonium salts may include: ammonium sulfate, ammonium hydrogen sulfate, ammonium hydrogen carbonate, ammonium phosphate, ammonium hydrogen phosphate, ammonium dihydrogen phosphate, ammonium hydrogen phosphate, ammonium pyrophosphate, ammonium halide, and ammonium nitrate Inorganic acid salts; And organic acid salts such as ammonium acetate (eg, ammonium carboxylate). Examples of preferred ammonium salts include ammonium dihydrogen phosphate.

In the case of using an ammonium salt, the amount of the ammonium salt added is preferably expressed in an amount of substance per kg of solvent, preferably in the range of 0.001 mmol / kg to 100 mmol / kg.

Examples of oxygen used in this reaction include molecular oxygen such as oxygen gas. The oxygen gas may be oxygen gas prepared by an inexpensive pressurized swing method, or may be high purity oxygen gas prepared by cryogenic separation or the like as necessary. Oxygen-containing gas (eg air) may also be used in place of pure oxygen gas.

Hydrogen gas is generally used as hydrogen used in this reaction.

Oxygen and hydrogen gas used for this reaction can also be provided to this process, after diluting with the gas for dilution which does not inhibit the progress of this reaction. As the diluent gas, nitrogen, argon or carbon dioxide may be used. In addition, organic gas, such as methane, ethane and propane, can be used as a diluent gas, unless the separation with the propylene oxide obtained after this reaction becomes remarkably difficult. The amount of oxygen and hydrogen used, and the concentration of the diluent gas for diluting these gases can be adjusted according to other conditions such as the amount of material of propylene used or the reaction scale.

The molar ratio between oxygen and hydrogen charged in the reactor is represented by oxygen: hydrogen, preferably in the range from 1:50 to 50: 1, more preferably in the range from 1: 5 to 5: 1. It is preferable from the viewpoint of stability that the molar ratio should be set so that the amount of hydrogen in the gas phase in the reactor of the present process is outside the range causing hydrogen explosion.

The amount of propylene in this reaction is preferably in the range of 1: 5 to 5: 1, expressed in terms of propylene: oxygen (molar ratio to oxygen used). The process may use a continuous reactor or may use a batch reactor; It is preferable to use a continuous reaction apparatus industrially; It is preferable to perform this reaction continuously using the said continuous reaction apparatus. When carrying out this reaction continuously, a partial pressure ratio can be controlled using the flow volume of oxygen, hydrogen, and propylene supplied to a reactor.

The reactor used in the present process may be a fixed bed reactor, a stirred tank, or the like as described above, and examples thereof include, in particular, a flow-through fixed bed reactor and a flow-through slurry-complete mixing reactor.

The reaction temperature of the present reaction is preferably in the range of 0 ° C to 150 ° C, more preferably in the range of 40 ° C to 90 ° C.

On the other hand, the reaction pressure of the present reaction is preferably in the range of 0.1 MPa to 20 MPa, more preferably in the range of 1 MPa to 10 MPa as the gauge pressure.

<Other Processes>

The reaction mixture taken out from the reactor via this step contains by-products such as propylene glycol in addition to the propylene oxide and unreacted remaining propylene, hydrogen and oxygen. In addition, a small amount of propane by-products may be included, and when a solvent is used in the present reaction, the solvent may be included in the reaction mixture. The desired propylene oxide can be separated from the reaction mixture by purification means known in the art. Examples of purification means include separation by distillation.

When the reaction is carried out in the presence of a Pd-free carbon material, the production rate of propylene oxide is higher than when the reaction is performed without a Pd-free carbon material. That is, according to the present invention, propylene oxide can be produced at a high reaction rate. Thus, the present reaction not only can produce propylene oxide with improved hydrogen efficiency, but also has the effect that it becomes easy to separate and purify propylene oxide from the reaction mixture.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples.

In the Example, the measurement was performed in the following manner.

Element Analysis

1. The contents of Ti (titanium) and Si (silicon) were determined by alkali melting, dissolution in nitric acid, and ICP emission spectroscopic analysis.

2. The content of Pd (palladium) in the Pd-supported catalyst was determined by microwave decomposition and ICP emission spectroscopy.

3. Presence of Pd in the Pd-free carbon material was determined by semi-quantitative analysis based on the FP (fundamental parameter) method using fluorescent X-ray ZSX Primus II (Rigaku Corp.). The measuring range is from F to U.

Lower detection limit: <0.01% by weight

<X-ray powder diffraction (XRD)>

The X-ray powder diffraction pattern of the sample was obtained using the following apparatus and conditions.

Device: Rigaku Corp. Priest RINT2500V

Source: Cu Xα X-ray

Output: 40 kV-300 mA

Scan Range: 2θ = 0.75 to 30 °

Scan rate: 1 ° / min.

X 선 회절 패턴이 EP1731515A1 의 도 1 의 것과 유사한 경우, 시료는 Ti-MWW 전구체로 확인되었다.

When the X-ray diffraction pattern was similar to that of FIG. 1 of EP1731515A1, the sample was identified as Ti-MWW precursor.

X 선 회절 패턴이 EP1731515A1 의 도 2 의 것과 유사한 경우, 시료는 Ti-MWW 로 확인되었다.

When the X-ray diffraction pattern was similar to that of FIG. 2 of EP1731515A1, the sample was identified as Ti-MWW.

<UV-Visible Absorption Spectrum (UV-Vis)>

The mortar was used to grind the samples and pelleted (7 mmΦ). The UV-visible absorption spectrum of this pellet was measured using the following apparatus and conditions:

Device: Diffuse Reflective Accessory (Praying Mantis, manufactured by HARRICK Scientific Products)

Accessories: UV-visible spectrophotometer (manufactured by JASCO Corp. (V-7100))

Pressure: atmospheric pressure

Measured value: Reflectance

Data collection time: 0.1 seconds

Bandwidth: 2 nm

Measurement wavelength: 200 to 900 nm

Slit Height: Half-Open

Data Collection Interval: 1nm

Baseline correction (baseline): BaSO ₄ pellets (7 mmΦ)

200 nm 내지 400 nm 의 파장 영역의 UV-가시 흡수 스펙트럼이 210 nm 내지 230 nm 의 파장 영역에서 최대 흡수 피크를 가졌을 때, Ti 함유 실리케이트 시료는 티타노실리케이트로 확인되었다.

When the UV-visible absorption spectrum in the wavelength region of 200 nm to 400 nm had the maximum absorption peak in the wavelength region of 210 nm to 230 nm, the Ti-containing silicate sample was identified as titanosilicate.

Preparation Example 1 [Preparation of Titanosilicate Catalyst (Titanosilicate A)]

In an autoclave, 899 g of piperidine, 2402 g of ion-exchanged water, 46 g of TBOT (tetra-n-butyl ortho titanate), 565 g of boric acid, and fumed silica (cab-o manufactured by Cabot Corp.) under an air atmosphere at room temperature 410 g of -sil M7D) were charged and these were dissolved under stirring at this temperature under stirring to prepare a gel. After the obtained gel was aged for 1.5 hours, the autoclave was tightly sealed. The aged gel was further heated to 150 ° C. over 8 hours under stirring, and then maintained at this temperature for 120 hours to hydrothermally synthesize and cool. After hydrothermal synthesis the reaction product was a suspension solution. After the obtained suspension solution was filtered, the filter cake was washed with ion-exchanged water until the pH of the filtrate was 10.3. Next, the filter cake was dried (drying temperature: 50 ° C.) until no weight loss was seen, thereby obtaining 524 g of a layered compound. After adding 3750 mL of 2M aqueous nitric acid solution and 9.6 g of TBOT to 75 g of the obtained layered compound, the mixture was heated for 20 hours while maintaining the reflux. After cooling, filtration was carried out, the filter cake was washed with ion-exchanged water until the pH of the filtrate was near neutral, and vacuum dried at 150 ° C until no weight loss was observed. The product obtained was a white powder. The procedure was carried out several times to give a total of 120 g of white powder (hereinafter referred to as "white powder A1").

The white powder A1 was calcined at 530 ° C. for 6 hours to obtain a white powder. The procedure was carried out several times to give a total of 108 g of powder (hereinafter referred to as "white powder A2").

In an autoclave, 300 g of piperidine, 600 g of ion-exchanged water, and 80 g of the white powder A2 obtained above were charged in an air atmosphere at room temperature, and dissolved under stirring at the above temperature and the atmosphere to prepare a gel. After the obtained gel was aged for 1.5 hours, the autoclave was tightly sealed. The aged gel was further heated to 160 ° C. over 4 hours under stirring, followed by hydrothermal synthesis by holding at this temperature for 24 hours. After hydrothermal synthesis the reaction product was a suspension solution. After the obtained suspension solution was filtered, the filter cake was washed with ion-exchanged water until the pH of the filtrate was 9.6. Next, the filter cake was dried in vacuo at 150 ° C. until no weight loss was seen to obtain a white powder. This white powder is hereinafter referred to as "white powder A3".

A three-necked glass flask was charged with 175 mL of toluene and 4.0 g of the white powder A3 thus obtained under an air atmosphere at room temperature and heated under reflux for 2 hours. After cooling, filtration was performed and the filter cake was further washed with 500 mL of acetonitrile / ion exchange water = 4: 1 (weight ratio). The filter cake was further vacuum dried at 150 ° C. until no weight loss was seen, yielding 3.6 g of white powder. Measurement of the X-ray diffraction pattern (FIG. 1) and UV-visible absorption spectrum (FIG. 2) of the white powder confirmed that the white powder was a Ti-MWW precursor (hereinafter, the white powder was referred to as Ti-MWW precursor A ).

Ti-MWW precursor A had a Ti content of 2.08 wt% and a Si content of 36.4 wt%. The calculated molar ratio of Ti / Si from Ti content and Si content was 0.034.

The Ti-MWW precursor A was subjected to an activation treatment as described below.

Ti-MWW precursor A (0.6 g) was added to 100 g of ion-exchanged water / acetonitrile = 1/4 (weight ratio) solution containing 0.1% by weight of hydrogen peroxide, treated at room temperature for 1 hour, and then filtered and filtered Was washed with 500 mL of ion exchanged water and suspended in 50 g of ion exchanged water / acetonitrile = 1/4 (weight ratio) solution. After suspension, filtration and drying were carried out to obtain titanosilicate A.

Preparation Example 2 [Preparation of Titanosilicate Catalyst (Titanosilicate B)]

In an autoclave, 898 g of piperidine, 2403 g of ion-exchanged water, 112 g of TBOT (tetra-n-butyl ortho titanate), 565 g of boric acid, and fumed silica (cab-o manufactured by Cabot Corp.) under an air atmosphere at room temperature 409 g of -sil M7D) were charged and these were dissolved under stirring at this temperature under stirring to prepare a gel. After the obtained gel was aged for 1.5 hours, the autoclave was tightly sealed. The aged gel was further heated to 150 ° C. over 8 hours under stirring, and then maintained at this temperature for 120 hours to hydrothermally synthesize and cool. After hydrothermal synthesis the reaction product was a suspension solution. After the obtained suspension solution was filtered, the filter cake was washed with ion-exchanged water until the pH of the filtrate was about 10. The filter cake was then dried at 50 ° C. in a convection drying oven until no weight loss was seen, yielding 517 g of layered compound. After adding 3750 mL of 2M aqueous nitric acid solution to 75 g of the obtained layered compound, the mixture was heated for 20 hours while maintaining reflux under atmospheric pressure. After cooling, filtration was carried out, the filter cake was washed with ion-exchanged water until the pH of the filtrate was near neutral, and vacuum dried at 150 ° C until no weight loss was observed. The product obtained was a white powder (hereinafter referred to as "white powder B1").

The white powder B1 was calcined at 530 ° C. for 6 hours to obtain a white powder (hereinafter referred to as “white powder B2”). The procedure was performed several times.

In an autoclave, 300 g of piperidine, 600 g of ion-exchanged water, and 100 g of the white powder B2 obtained above were charged in an air atmosphere at room temperature, and dissolved under stirring at the above temperature and the atmosphere. After the obtained mixture was aged for 1.5 hours, the autoclave was tightly sealed. The aged mixture was further heated to 150 ° C. over 4 hours under stirring, and then the temperature was adjusted to 160 ° C. Hydrothermal treatment was performed for 1 day. After hydrothermal treatment the product was a suspension solution. After the obtained suspension solution was filtered, the filter cake was washed with ion-exchanged water until the pH of the filtrate was about 9. Next, the filter cake was dried in vacuo at 150 ° C. until no weight loss was seen to obtain a white powder. The white powder obtained had a Ti content of 1.74 wt% and a Si content of 36.6 wt%. The calculated molar ratio of Ti / Si from Ti content and Si content was 0.028.

UV-visible absorption spectrum (FIG. 3) measurement showed that the white powder was titanosilicate (hereinafter referred to as “titanosilicate B”).

Preparation Example 3 [Preparation of Titanosilicate Catalyst (Titanosilicate C)]

A white powder was prepared in the same manner as in Preparation Example 2. The white powder is hereinafter referred to as "titanosilicate C".

Preparation Example 4 [Preparation of Pd-supported Catalyst A (Pd / Activated Carbon (AC) Catalyst)]

Activated carbon (Carborafin-6, manufactured by Japan Enviro Chemicals. Ltd.) Was prepared by washing in advance with 10 L of high-temperature ion-exchanged water and drying at 300 ° C. for 6 hours. Furthermore, dispersion A was prepared from 0.3 mmol of colloidal palladium (manufactured by JGC C & C) (palladium equivalent) and ion exchanged water.

A 1 L branched flask was charged with 3 g of washed activated carbon and 300 mL of ion-exchanged water under air atmosphere at room temperature, followed by stirring. To the obtained suspension, 40 mL of dispersion A was slowly added dropwise at room temperature under an air atmosphere. After completion of the dropwise addition, the suspension was further stirred at this temperature under the atmosphere for 6 hours. After stirring was completed, water was removed using a rotary evaporator, and the residue was vacuum dried at 80 ° C. for 6 hours, and then further heated at 300 ° C. for 6 hours under a nitrogen atmosphere to thereby provide a Pd / activated carbon (AC) catalyst (hereinafter, “Pd- A supported catalyst A "was obtained.

Preparation Example 5 [Preparation of Pd-supported Catalyst B (Pd / Activated Carbon (AC) Catalyst)]

Activated carbon B for a carrier of a Pd-supported catalyst was prepared as follows. 20 g of activated carbon (manufactured by Japan Enviro Chemicals. Ltd., TOKUSEI SHIRASAGI) was washed with 10 L of high temperature ion-exchanged water, and then dried under nitrogen atmosphere at 300 ° C for 6 hours.

1 L of eggplant flasks were charged and stirred with 5 g of activated carbon B obtained above and 300 mL of ion-exchanged water under an air atmosphere at room temperature, followed by 0.49 g of colloidal palladium solution (manufactured by JGC C & C) and ion-exchanged water. The prepared dispersion was slowly added dropwise to the flask under stirring. Wherein the colloidal palladium solution contained 3.1 wt.% Pd. After completion of the dropwise addition, the suspension was further stirred at this temperature under the atmosphere for 6 hours. After stirring was completed, water was removed using a rotary evaporator, and the residue was vacuum dried at 80 ° C. for 6 hours, and then further heated at 300 ° C. for 6 hours under a nitrogen atmosphere to thereby provide a Pd / activated carbon (AC) catalyst (hereinafter, “Pd- The supported catalyst B "was obtained.

The Pd content of the Pd-supported catalyst B calculated by the amount of filling of the material was 0.27 wt%.

Preparation Example 6 [Preparation of Pd-supported Catalyst C (Pd / Activated Carbon (AC) Catalyst)]

Activated carbon C for a carrier of the Pd-supported catalyst was prepared as follows. 18 g of activated charcoal (manufactured by Japan Enviro Chemicals. Ltd., TOKUSEI SHIRASAGI) was washed with 10 L of high-temperature ion-exchanged water.

After washing, a full amount of activated carbon C was charged into a 1 L eggplant flask with 300 mL of ion-exchanged water at room temperature to obtain a mixture, and the mixture was stirred.

After stirring, a dispersion prepared from 5.9 g colloidal palladium solution (manufactured by JGC C & C) and ion-exchanged water was slowly added dropwise to the flask under stirring. Here, the colloidal palladium solution contained 3.1 wt% Pd. After completion of the dropwise addition, the suspension was further stirred at this temperature under the atmosphere for 6 hours. After stirring was completed, water was removed using a rotary evaporator, and the residue was vacuum dried at 80 ° C. for 6 hours, and then further heated at 300 ° C. for 6 hours under a nitrogen atmosphere to thereby provide a Pd / activated carbon (AC) catalyst (hereinafter, “Pd- A supported catalyst C "was obtained.

The Pd content of the Pd-supported catalyst C calculated by the filling amount of the material was 1.0% by weight.

Production Example 7 [Preparation of Pd-Free Carbon Material (Activated Carbon A)]

Commercially available activated carbon (TOKUSEI SHIRASAGI, manufactured by Japan Enviro Chemicals. Ltd.) Substantially free of Pd was used in this production. As mentioned above, it was confirmed that the activated carbon obtained by fluorescence X-ray analysis was substantially free of Pd. 20 g of the activated carbon was washed in the order of 1 L of ion-exchanged water and 10 L of high-temperature ion-exchanged water, and heated at 300 ° C. for 6 hours under a nitrogen atmosphere to obtain activated carbon A.

Example 1 (Method for Producing Propylene Oxide)

0.5 L autoclave was used as reactor. In the autoclave, 0.6 g of titanosilicate A, 0.02 g of Pd-supported catalyst A and 2 g of activated carbon A were charged. A solution containing anthraquinone dissolved in a raw material gas having a volume ratio of propylene / oxygen / hydrogen / nitrogen of 8/11/4/77 and water / acetonitrile = 1/4 (weight ratio) in this autoclave (anthraquinone concentration: 0.7 mmol / kg) were fed at a feed rate of 16 L / hr and a feed rate of 108 mL / hr, respectively, to react propylene, oxygen and hydrogen in the liquid phase in the reactor, after which the reaction mixture was extracted through a filter. A continuous reaction was carried out. Set the reaction temperature to 60 ° C; Set the pressure to 0.8 MPa (gauge pressure); The residence time of the liquid fed into the reactor was set to 90 minutes.

After 5 hours of reaction, the liquid phase and gas phase of the extracted reaction product were analyzed by gas chromatography. As a result, the production rate of propylene oxide was 4.06 mmol / hr, and the propylene oxide selectivity (molar amount of propylene oxide produced / (of propylene oxide produced) Molar amount + molar amount of propylene glycol produced + molar amount of propane produced)) is 93% and propane by-product selectivity (molar amount of produced propane / (molar amount of produced propylene oxide + molar amount of propylene glycol produced + molar amount of produced propane) Molar amount) was 3.2% and the hydrogen efficiency (molar amount of propylene oxide produced / molar amount of hydrogen consumed) was 53%.

Example 2 (Method for Producing Propylene Oxide)

First, the activation treatment of titanosilicate C using a hydrogen peroxide solution was performed as described below.

Titanosilicate C (2.28 g) was added to 100 g of ion-exchanged water / acetonitrile = 1/4 (weight ratio) solution containing 0.1% by weight of hydrogen peroxide, treated at room temperature for 1 hour, filtered and the filter cake Washing with ion-exchanged water produced activated titanosilicate C. After the activation treatment, the entire amount of the activated titanosilicate C described above was suspended in 100 ml of ion-exchanged water / acetonitrile = 3/7 (weight ratio) solution and charged to the reactor.

Commercially available activated carbon (TOKUSEI SHIRASAGI, manufactured by Japan Enviro Chemicals. Ltd.) That was substantially free of Pd as a Pd-free carbon material was used for the reaction. The Pd content of the activated carbon was confirmed in the same manner as in Preparation Example 7, and the activated carbon was substantially free of Pd.

0.3 L autoclave was used as reactor. In the autoclave, 1.06 g of Pd-supported catalyst C and 2.1 g of the Pd-free activated carbon were charged to the autoclave, and then the entire amount of ion exchanged water / acetonitrile solution containing activated titanosilicate C was charged to the autoclave. .

A solution containing an anthraquinone and diammonium hydrogen phosphate dissolved in an autoclave in a dilution raw material gas having a volume ratio of oxygen / hydrogen / nitrogen of 3/4/93 and ion-exchanged water / acetonitrile = 3/7 (weight ratio) ( Anthraquinone concentration: 0.7 mmol / kg, diammonium hydrogen phosphate concentration: 3.0 mmol / kg) and liquid propylene at a feed rate of 263 L / hr (0 ° C., 1 atm), 90 g / hr, and 36 g / hr Feeding at a rate, propylene, oxygen and hydrogen were reacted in the liquid phase in the reactor, and then a continuous reaction was conducted in which the reaction mixture was extracted through a filter. Set the reaction temperature to 50 ° C .; Set the pressure to 4.0 MPa (gauge pressure); The residence time of the solution fed into the reactor was set to 1 hour. This reaction was continued for 4.5 hours before sampling.

During the reaction, the reaction mixture was adjusted to keep titanosilicate C at 2.28 g, Pd-supported catalyst at 1.06 g, and Pd-free activated carbon at 2.1 g in 90 g of its solvent.

The liquid phase and gas phase of the reaction product extracted after 4.5 hours of reaction were analyzed by gas chromatography analysis. As a result, the production rate of propylene oxide was 162 mmol / hr, the hydrogen consumption rate was 281 mmol / hr, the propylene oxide selectivity was 87%, It was confirmed that the hydrogen efficiency is 58%.

Comparative Example 1 (Method for Producing Propylene Oxide Without Pd-Free Carbon Material)

Except not using the activated carbon A, the same procedure as in Example 1 was carried out to produce propylene oxide. After 5 hours, the liquid phase and gas phase of the extracted reaction product were analyzed by gas chromatography. As a result, the yield of propylene oxide was 3.50 mmol / hr, the propylene oxide selectivity was 89%, the propylene by-product selectivity was 5.3%, hydrogen It was confirmed that the efficiency is 45%.

Comparative Example 2 (Producing Method of Propylene Oxide without Pd-Free Carbon Material)

The same procedure as in Example 2 was carried out except that 2.28 g of titanosilicate B instead of titanosilicate C and 3.17 g of Pd-supported catalyst B instead of Pd-supported catalyst C were used without charging Pd-free activated carbon to the reactor. It carried out and performed the manufacturing reaction of propylene oxide. The liquid phase and gaseous phase of the reaction product extracted after 4.5 hours of reaction were analyzed by gas chromatography, and the result was 146 mmol / hr of propylene oxide, 305 mmol / hr of hydrogen consumption, 86% of propylene oxide selectivity, It was confirmed that the hydrogen efficiency is 48%.

The present invention is very useful as a method for producing propylene oxide, which is an intermediate of various industrial materials.

Claims (9)

A process for producing propylene oxide comprising reacting propylene, hydrogen and oxygen in a liquid phase in the presence of a Pd-supported catalyst, a titanosilicate catalyst and a Pd-free carbon material. The method of claim 1, wherein the Pd-supported catalyst consists of a carrier and Pd supported by the carrier, and the Pd-free carbon material does not form a carrier of the Pd-supported catalyst. The process of claim 1 wherein said Pd-supported catalyst comprises at least one carrier selected from the group consisting of silica, alumina, activated carbon and carbon black. The method of claim 1 wherein said Pd-supported catalyst comprises a carrier selected from the group consisting of activated carbon and carbon black. The method according to any one of claims 1 to 4, wherein the Pd-free carbon material is activated carbon, carbon black or mixtures thereof. The method according to any one of claims 1 to 4, wherein the Pd-free carbon material is activated carbon. The process according to claim 1, wherein the process further comprises reacting propylene, hydrogen and oxygen in the liquid phase in the presence of a polycyclic compound having from 2 to 30 rings. 8. The method of claim 7, wherein said polycyclic compound is a condensed polycyclic aromatic compound. 8. The method of claim 7, wherein said polycyclic compound comprises anthraquinone.

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